


Challenge Accepted

by Shaed



Category: Free!
Genre: But I regret nothing, First Kiss, First Time, Loss of Virginity, M/M, Mention of Captain Tripod, Not My Fault, Sorry Not Sorry, Tachibana Makoto Has A Large Cock, Twitter is conduit of all things EVIL, Will I Still Respect Me in the Morning?, also, and my friends are terrible enablers, because no Free! porn is complete without mentioning Makoto's junk, denial AU SeiHaru porn, except the part I wrote the whole thing, seriously
Language: English
Status: Completed
Published: 2014-06-16
Updated: 2014-06-16
Packaged: 2018-02-04 21:19:17
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,788
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1793536
Author URL: https://archiveofourown.org/users/Shaed/pseuds/Shaed
Summary: <blockquote class="userstuff">
              <p>An AU take on Chapter 7 of <a href="http://archiveofourown.org/users/Ad_Astra/pseuds/Ad_Astra">Ad_Astra</a>’s <b><a href="http://archiveofourown.org/works/1026756">Denial is Not Just a River in Egypt</a></b>. AKA Twitter is the conduit of All Things Evil.</p><p> </p><p>  <b>NOW WITH CONTINUATION BY THE LOVELY <a href="http://archiveofourown.org/users/unsospiro/pseuds/unsospiro">unsospiro</a>: <a href="http://archiveofourown.org/works/1911003">we were breathing underwater</a></b></p>
            </blockquote>





	Challenge Accepted

**Author's Note:**

  * For [Ad_Astra](https://archiveofourown.org/users/Ad_Astra/gifts).
  * Inspired by [Denial is Not Just a River in Egypt](https://archiveofourown.org/works/1026756) by [Ad_Astra](https://archiveofourown.org/users/Ad_Astra/pseuds/Ad_Astra). 



> First of all, this is an AU take on Chapter 7 of [Ad_Astra](http://archiveofourown.org/users/Ad_Astra/pseuds/Ad_Astra)’s **[Denial is Not Just a River in Egypt](http://archiveofourown.org/works/1026756)**. If you haven’t read it yet, SHAME ON YOU, what are you even doing here? D: D: D: 
> 
> Inspired by the lovely cohorts over at Twitter, all of whom are terrible, terrible enablers. Credit for the original idea goes to Sospi, as explained by Astra:
> 
>  **Astra:** It’s the alternate ending to Denial ch 7. Sei:"Never tried it Nanase?" Haru: "Never interested." Sei: *grins* "I can change that."
> 
> Except there was a tiny problem:
> 
>  **Astra:** HOW will it even go orz Haru swings wildly from clinical to curious to YOU ME FUCK NOW.  
>  **Shaed:** ...That could work. :D
> 
> This was the bastard lovechild. Also known as "Hips Don't Lie" and "Better Than Saba" – and I would totally have used them both except the darn fic doesn't actually MENTION anything about lying OR saba, sadness. D: We will always have "Denial AU SeiHaru Porn" I guess? XD
> 
> Thank you, [Ad_Astra](http://archiveofourown.org/users/Ad_Astra/pseuds/Ad_Astra), for the beta! All mistakes are subsequent to beta-session and therefore entirely mine alone.

“It’s kind of true though,” Nanase says thoughtfully. “I do everything with you and Makoto except for the sex.”

Seijuurou jostles him playfully with an elbow. “Aww, Nanase never tried it?”

Nanase shakes his head. “Never interested.”

Seijuurou raises an eyebrow. "I can change that," he drawls before he can think better of it. Matusoka is too busy sputtering to even notice, but Nanase’s brow quirks up at that.

Matsuoka finally recovers enough to start yelling why is he the girlfriend, Nanase is the pretty one, blah blah. Seijuurou pays him little heed, distracted by the brief glance Nanase shoots him, at once assessing and intrigued, before Nanase turns back to retort something about Matsuoka's bath products.

Seijuurou likes to think of himself as open-minded. He's been stuck in an all boys' school for three of the most hormonal years of a teenage boy's life. Cute girls aren't easy to come by, and often require more time than he's willing to divert from his pool time. If he weren't willing to experiment a little, it would have been very frustrating three years. Frustration affects performance, and _that_ , he cannot allow.

Nanase, though. Given how much interest Nanase usually shows in non-aquatic bodies, which is a grand total of zero, Seijuurou hadn't expected that little glance. 

Ah well. He doubts anything will come out of it. So he waves off Matsuoka, who huffs away with a basket which looks suspiciously like a bath set, and leaves them to it.

* * *

As another perk of attending an all boys' school, Seijuurou hears (and makes) his share of sex jokes all the time. In fact he would have entirely forgotten the quip he'd made to Nanase if it hadn't been for that odd expression on Nanase's face. Still, he would have thought he'd be the last person Nanase would pursue that with.

Which is why he is really surprised to receive a phone call from Nanase a week later.

"So? What can I do for you?" he asks after putting Nanase on speaker phone, his attention still mostly on the paper he was typing when the phone rang.

There is a short silence on the other end. "I thought about what you said," Nanase starts, then pauses. "I want to take you up on your offer."

Seijuurou stops typing to stare at the phone. "Which offer?" Seijuurou asks, although he can guess. He can't pretend he hasn't thought about it, but he wants to make sure they are on the same page.

"About changing my lack of interest in sex," Nanase answers, voice so incongruously deadpan that Seijuurou has to blink to make sure he hasn't imagined the words.

Seijuurou really had been mostly joking last week. Not entirely, but mostly. And he _really_ hadn't expected Nanase to pursue the topic. At least not with him. "Okay," he says, drawing out the syllables thoughtfully. "Any particular reason for this development?"

He can practically hear Nanase shrug on the other side. "You offered. I'm curious."

Seijuurou raises an eyebrow even though he knows Nanase can't see him. He can turn Nanase down, easy. Pass it off as a joke. Instead, what escapes his mouth is, "If you're sure."

"I said so, didn't I?" Nanase sounds a bit miffed. "Are you available today?"

Talk about racing ahead. Seijuurou can't help a smirk. "Sure. You wanna come over?" Samezuka has an indoor pool, after all. If Nanase changes his mind at the last minute, at least they'll have a back-up plan.

"I want to swim first," Nanase says, which just makes him laugh. "I can be there in an hour."

"Figured that. Meet you at the pool, then. I'll leave the door open."

"Alright."

"How did you get my number?" Seijuurou asks before Nanase hangs up. _And what did you tell them?_ he adds mentally.

"Rin's sister."

Seijuurou lets out a sound that's halfway between amused and horrified and hopes the poor girl didn't ask what Nanase wants his number for. Because he has a feeling Nanase would have told her the truth and wouldn't that be interesting to explain?

"See you in an hour," Seijuurou says instead of airing his concerns, to which Nanase hums in affirmative, then hangs up. He shakes his head in disbelief, then dismisses the thought. He still has a paper to finish, and some warming up to do before Nanase arrives.

* * *

When Nanase arrives at the pool, he doesn't even glance at Seijuurou, diving straight for the water. Then he swims a couple rounds before he returns to the diving blocks, where Seijuurou is watching him.

"You wanna race?" Seijuurou asks, and Nanase shrugs. He isn't Matsuoka and isn't that keen on racing on his days off, but Seijuurou _is_ a competitive swimmer at heart and Nanase is a fine opponent any old day. "Y'know, I'm not your wife or girlfriend, so I'd appreciate a verbal answer, Nanase."

"If you want," Nanase replies carelessly, ignoring the rest of the dig.

"Get up here, then."

Nanase pulls himself from water with unhurried grace that reminds Seijuurou of a dolphin lifting out of the water. They step on the blocks together, and belatedly, Seijuurou recalls they don't have anyone to referee—

"On three," Nanase says. "Two."

"One," they say together, and dive.

Underwater, nothing else matters. Just his body cutting through water. Sweet ache of muscles. Speed. There are three things Seijuurou loves the most in his life: swimming, winning, and an opponent who can push him to break records.

Nanase is two out of the three. Possibly three out of three, although they'd hit the wall so closely that he honestly can't tell.

"Well?" he prompts as they both pant.

Nanase shrugs. "Couldn't tell. Want to go again?"

Seijuurou laughs, bright and sharp. "Yeah, why not?"

* * *

After four more rounds they make it back to Seijuurou's room. He has a single room, so privacy is no concern. But when the door closes behind them, Seijuurou can't help feeling a mite weirded out.

"Why me?" he asks bluntly. He doesn't think Nanase is particularly attracted to him. Plus Nanase said that he has never been interested before. If it's out of simple curiosity, this is an odd and slightly disturbing way of going about it.

Nanase makes a little sound, non-committal, and purses his lips. "I usually go to Makoto for everything else. I can't, about this."

There is that, Seijuurou supposes. Still, he wants to cover all his bases. "You ever done this before?"

"No."

Seijuurou has about figured that. "You sure about this?"

This time there is a split second delay before Nanase meets his eyes. "Yes." Then, a crease enters between his brows. "What's the big deal? I've never been interested before. But you offered, and I’m curious.”

Seijuurou can't help a short bark of laughter. Seriously, Nanase is weird even for one of Matsuoka’s friends. "I’m not sure about you, but most people attach some significance to their first time.” Nanase shrugs again, and he decides to let the sleeping lions lie. It's not as if he gets young attractive virgins begging him to deflower them every day. He may as well take the opportunity offered. "Okay, then." He pulls off his shirt and raises an eyebrow at Nanase. "Well?"

Nanase sheds his clothing without so much as a shrug. Seijuurou has seen him naked before. A week before, to be exact. But it's surreal, the way Nanase strips without a shred of self-consciousness. At least his dick is taking an interest in their intended activity for the afternoon; for a moment or two, he'd worried just because their situation is so out of touch with normalcy. The same cannot be said for Nanase, but that's precisely what Seijuurou is here for today.

"You ever try so much as kissing someone?" Seijuurou asks once they're both naked, stepping closer to Nanase.

"I tried to kiss Rin last week," Nanase answers thoughtfully. Before Seijuurou can digest that he continues, "He pushed me into the pool."

"I thought Matsuoka was dating Tachibana?"

Nanase shrugs minutely. "It was a test. Rin didn't want to. That's all I wanted to know."

Seijuurou shakes his head and decides to leave that alone. "You and Matsuoka really are something else," he says, repeating what he'd said the night before. Without further ado, he tips up Nanase's chin and presses his lips against Nanase's, keeping the pressure gentle. The semi-hysterical thought occurs to him that he is Nanase's first kiss, in fact soon to be first everything else. The day can't get any weirder, can it?

It takes a couple tries before Nanase takes the hint and opens his mouth. At least Nanase is a quick study. So he loses no time introducing tongue, and is amused to note Nanase immediately follows the suit, returning the kiss with growing confidence. Despite himself, Seijuurou finds himself kind of getting into it.

"Let me know if you want to slow down. Or stop," Seijuurou tells him when they pull apart. Is it just him or did Nanase look a little breathless? "Breathe through your nose," he advises him before pulling him into another kiss.

Aside from his looks, which definitely work in his favor, there is something appealing in the utter unselfconsciousness with which Nanase does everything. Nanase's soft, Seijuurou can feel it, an awkward contrast to his own half-hard state. He intends to change that in short order.

There is no reason to beat around the bushes, he figures, and unceremoniously reaches between Nanase's legs. Predictably Nanase jumps, but doesn't pull away, so Seijuurou takes it as a permission to continue. For a short while nothing happens, and just when Seijuurou is wondering if he should feel insecure or possibly offended, Nanase's cock twitches.

Every teenage boy has done at least this. This is familiar. It takes just a few tries to figure out the rhythm Nanase seems to prefer, and Seijuurou strokes him to full hardness easily enough.

"Is this," Nanase starts, then stops. "Should we move to the bed?"

Seijuurou can't read Nanase's face that well from this angle, so decides to take the invitation at face value. "Sure."

Nanase is a little flushed, but still doesn't look embarrassed or even bothered by his current state. And he eases himself down on Seijuurou's bed with a certain deliberation that makes Seijuurou feel strangely motivated if somewhat irritated. It's a trifle galling to his pride that Nanase still doesn't look actively _interested_ even when he's aroused. Nakagawa is going to laugh at him, tell him he's too prone to thinking with his dick, but come on, they are teenage boys. Nanase's detachment is unnatural.

When Seijuurou climbs on the bed and reaches for Nanase again, the boy stirs impatiently under him, then lets out a soft huff of a breath. "What's the difference between this and doing it alone?" he asks, sounding almost annoyed even with his cock full and hard in Seijuurou's hand.

Seijuurou stiffens despite himself. Oh, Nanase just didn't.

"This, for one," he drawls, and moves down to take Nanase in his mouth. He does have the benefit of experience here, and this is one thing a guy can't improve on without practice. Nanase's back arches and he thrusts up impatiently, but Seijuurou is having none of that. Sure, this is supposed to be about making Nanase interested in sex, but it's still sex and he's not taking this in any direction but his own. So he pins Nanase's hips to the bed with both hands, lets out a questioning hum just to be a bastard. Nanase twists, testing his grip, but subsides with little more than a faintest sound. And it is _on_. Stupid male ego or not, Nanase is not leaving his bed without properly screaming his head off first.

So Seijuurou licks experimentally, tightens his lips and relaxes his throat, and makes a concerted effort to suck Nanase's brain out through his dick. Fortunately for his poor abused ego, Nanase becomes a hell of a lot more enthusiastic in gratifyingly short amount of time. After a few more tries at dislodging Seijuurou, Nanase spreads his legs wider, plants his feet, and uses the newfound leverage to push down, hips drawing tight, obscene circles that makes Seijuurou laugh around Nanase's cock, and that makes Nanase groan, so it's a win all around. From fingers tightening in his hair, the tensing thighs, he knows Nanase's close, and considers his options. Unthinking, he makes another humming sound, thumb stroking over the boy's hole, and abruptly Nanase thrusts up, like he's been startled, and comes messily in Seijuurou's mouth.

Seijuurou sits back, rubbing his throat, but can't help feeling a bit smug as he surveys his work. Nanase looks dazed, and where's his never-been-interested-is-that-it attitude now? Seijuurou affectionately pats one firm thigh, admiring the way his tanned fingers stand out against the creamy skin. He almost regrets rushing ahead – alright, so maybe he can admit he let Nanase goad him into going faster than he'd intended. But the afternoon is young and so are they.

So he runs an inquisitive hand over Nanase's flank, caresses the soft skin of Nanase's thighs, and gets a tiny frown of confusion for his trouble.

"Wow. You really don't know anything about hooking up, do you?" he says wonderingly. What, did Nanase never watch porn either?

Nanase has to clear his throat a couple times, much to Seijuurou's smug pleasure. "I caught Rin and Makoto a couple times."

That's a little bit more than he would have wanted to know, to be frank, but something niggles at him. Unless Nanase’s in the habit of barging into private rooms, he doubts Nanase caught them doing anything more than making out or a quickie at best.

"Well, there's the basic point,” Seijuurou says. “And then there's technique. And style."

Nakagawa would have smacked him for that, but Nanase looks like he's on more familiar grounds. "Sex is like swimming, but there are different ways to do it?" he asks, and Seijuurou lets out a startled laugh.

"Something like that, yeah. Look, a lot of people learn how to swim so they don't die when dropped in the water. And some people are okay with just that."

"You're not," Nanase says, and it's half a question and half a statement of fact.

Seijuurou grins at him. "Why settle for less than the very best? Just takes practice. And willingness to learn."

Nanase actually looks intrigued now. Seijuurou smirks and waits as patiently as his own unsatisfied cock permits. "Show me," Nanase says simply, and Seijuurou allows himself a moment of satisfaction before kissing him again.

Nanase's skin is so pale despite all the swimming he must do outdoors. And soft. Smooth and unblemished, stretched taut over firm muscles. He also turns out to have delightfully sensitive nipples, and Seijuurou makes a mental memo to play with them more next time. If there is one.

Either way, Nanase's dick is definitely taking a more active interest now, stirring as he experimentally humps against Nanase. He reaches between them and wraps a hand around both their cocks, and the sound Nanase makes soothes his ego at last.

"See, your problem is you only think in terms of necessities," Seijuurou says, almost conversationally. "Sure, you can swim all by your lonesome. But doing it with somebody else is—" His voice nearly breaks over the word because Nanase actually humps back. "—more fun."

"More intense," Nanase agrees, breathless and flushed. "You have more incentive to reach your goal."

Seijuurou grins, bright and brash. "Exactly."

Then his world narrows down to heat and friction and the little hitching sounds Nanase makes in the back of his throat. Nanase's famed slim fingers join his, and he swears and comes, making a sticky mess between their bodies. While he recovers Seijuurou notes Nanase is still hard and wonders if he should feel vaguely guilty before remembering that's because Nanase already came once before. Still, they're young and there are other things they can do. It's not like his body won't catch up in a little bit.

"What else?" Nanase prompts, wrapping a leg around Seijuurou in an oddly intimate way that should have felt out of place but doesn't. It's Nanase, after all. Seijuurou doubts Nanase even notices it.

"What, you wanna go all the way?" Seijuurou is honestly a little surprised. Most boys their age, when fooling around for the first time, are generally comfortable with handjobs and have more or less reasonable idea of how blowjobs work. But most tend to shy away from penetrative sex, at least with another boy. Seijuurou may not share the usual male hang-ups about it, but that's not to say he's ignorant of them. "You even know how that works?"

Nanase gives a half-shrug. "Rin seems to like it."

"TMI, Nanase. Also, how do you even know?"

"They did it in my bathroom once. While they were over for a barbecue."

It's hard to tell with the deadpan voice, but Seijuurou has a sneaking feeling Nanase's telling it exactly like it is. "They got it on in your bathroom? Shit, I guess we're lucky they didn't get that far in our club showers." Then, Seijuurou's eyes narrow. "Wait, how do you know Tachibana topped?"

Nanase blinks. "Rin was having trouble sitting down afterward."

"To be fair, anyone would after fitting _that_ up his ass." Seijuurou shakes his head wonderingly. And he hasn't noticed any change in Matsuoka's time, either. He has new dawning respect for Matsuoka.

Nanase gives a tiny shrug and shifts, apparently unperturbed by the idea. "His time isn't affected. Unless you noticed otherwise."

"No," Seijuurou agrees. "But that's not to say it'd be comfortable...why are we even discussing Matsuoka and Captain Tripod again?"

Nanase remains annoyingly unconcerned. "If you're that worried you can let me put it in."

"What? No." The refusal is automatic and immediate. As a rule Seijuurou doesn't bottom often, but that's beside the point. The point is Nanase is younger and inexperienced and not even interested in sex until fifteen minutes ago. The point is that nobody should be brazen enough to suggest what Nanase just did, especially during his first time.

Nanase lets out a little huff, lifting his chin with a little shake that makes the soft dark hair fall gently around his pretty, pretty face. Nanase's dark blue eyes glimmer up at Seijuurou with an alarming intensity. "You said you could convince me," Nanase challenges, his oh-so-slim fingers tracing his spine all the way down to the tailbone.

"Damn straight," Seijuurou retorts without thinking, then realizes he swam right into that net. God damn it, Nakagawa's going to have a good laugh at his expense tomorrow. Nanase shifts against him, dips curious fingers below his tailbone, and Seijuurou very nearly forgets his annoyance. "Oh fine. Here, let me fetch something."

He retrieves his stash of condoms and lube he didn't bother to prepare earlier because he didn't think they'd get this far. "You know, you don't have to learn everything at once," Seijuurou reminds him. "We can practice. Take our time."

Nanase's smirk is now all bite. "Only if it's worth learning."

Seijuurou swears, and the amused look on Nanase's face briefly reminds him of a dolphin: all playful sweetness and people forget they're predators armed with sharp teeth and fierce intelligence. Quite possibly, he may end up regretting this whole thing in the morning.

Ah well. Mikoshiba Seijuurou lives for the challenge anyway. He tosses Nanase the square packet of foil and straddles him. "You need me to walk you through this part or what?"

Nanase shrugs and lets Seijuurou put a little drop of lube on his dick and roll a condom over it. Eh, at least Nanase is no Tachibana. He shouldn't end up too sore tomorrow. After a moment of fumbling with the recalcitrant tube, Nanase makes a sound of impatience and takes it from him, deftly uncapping the tube one-handed before looking over questioningly. Seijuurou nods and leans forward. "Start with one finger and work your way up," he advises simply, and Nanase complies without comment. For a first-timer Nanase's fingers are sure and skillful, prying him open with a gentle force.

By the time Nanase has three fingers inside him, Seijuurou is dangerously close to forgetting why this was a bad idea or how they even got into this whole mess. "Fuck, Nanase. Lube up your dick and do it already," he growls, and Nanase looks mildly surprised before giving him a tiny smile.

At least Nanase doesn't have to be told twice. Seijuurou feels Nanase's cock nudging at his hole, and sighs. "Fucking finally," he mutters and sinks down smoothly until they're flush against each other. And finally Nanase looks blissfully wrecked, and too stunned to care. Nanase's hips jerk with a strangled sound, and Seijuurou swallows his own moan, smirking down at him.

"Let me know," Seijuurou drawls, rising up teasingly slow, "when you're convinced." Without waiting for an answer he sinks down hard, wringing a desperate sound from Nanase, then does again.

He rides Nanase hard and fast, until Nanase catches on and matches him stroke for stroke, keeping pace with him. He's full, Nanase a slick heat inside him, and as much as Nanase shakes and moans under him, he knows he's not going to last, either. Seijuurou is determined to make Nanase come first, however, and sinks down harder. He leans back and Nanase's cock rubs his insides _just right_ , and he moans appreciatively, tightening. Nanase lets out a shout, sharp and cut short, head thrown back, and that gorgeous picture is burned on his retina when Seijuurou comes.

When he opens his eyes again, Nanase still looks undone, his eyes closed, and Seijuurou takes a moment to congratulate himself on a job well done. He takes another minute before moving off Nanase and stretching out next to him.

Nanase finally opens his eyes and turns his head to look at him seriously. "What does that feel like?"

Seijuurou chuckles, pleasantly surprised. "Tell you what. Why don't you let me show you next time?"

Nanase considers this. The comical gravity of his expression nearly sets Seijuurou off again, but he restrains himself. For one, he's curious about Nanase's virgin ass. It's quite a visual treat. It'd be interesting to find out how it feels around his dick.

"Alright," Nanase says. Seijuurou grins at him brightly. He's quite pleased with himself, but figures he has good reasons to be. "Next week?" Nanase continues, and Seijuurou gives in and laughs.

"Yeah, sure. Why not?"

_\-- June 2014_

**[ETA]** **NOW WITH CONTINUATION BY THE LOVELY[unsospiro](http://archiveofourown.org/users/unsospiro/pseuds/unsospiro): [we were breathing underwater](http://archiveofourown.org/works/1911003)**

**Author's Note:**

> I'm more active on Twitter than Tumblr for those painfully disappointed by my lack of updates on the latter. Sorry~!! It's @le_shaed for anyone who wants it? Just...er, be warned that all I EVER talk about on Twitter is smut. Seriously I have more NSFW tweets than not.
> 
> Lastly, a real-life event is looming close, and with seriously a LOT of regret, I have to put all fic-activity on hold until the end of this month, or possibly the second week of July. I'm very, very sorry to those waiting for Superposition update.
> 
> And thank you SO MUCH, ladies, for all your encouragement and enabling over at Twitter. You know who you are. ♥


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